What is the importance of self-value?

Self-esteem is important because it heavily influences people's choices and decisions. In other words, self-esteem serves a motivational function by making it more or less likely that people will take care of themselves and explore their full potential.

Why is it important to value and appreciate yourself?

The act of appreciating yourself and being thankful only to you is self-appreciation. For example, you can be grateful that innate talents and skills are given to you, or you can appreciate your shortcomings as well. On the other hand, self-esteem is a personal measure of one's self-worth. That's a judgment.